Dynamic navigation, invokers, and World Partition

Generation mode selector

Mode	Use when	Constraint
Static	Navigable collision does not change at runtime	Build/cook data; cheapest runtime
Dynamic Modifiers Only	Base surface is static; runtime obstacles/areas modify it	Cannot create arbitrary new navigable surface absent from base data
Dynamic	Runtime geometry changes require tile regeneration	Highest runtime generation cost
Dynamic + Navigation Invokers	Very large/procedural world needs local generation around seeds	Readiness radius, generation latency, and removal policy become gameplay constraints

Prefer the least dynamic mode that represents real changes.

Runtime modifier pattern

• Use NavModifierVolume or NavModifierComponent with an Area Class to change cost or mark NavArea_Null.
• For moving obstacles that should block rather than become walking surface, mark them as Dynamic Obstacles/appropriate modifiers so only affected data is dirtied.
• Batch or debounce frequent changes; continuous transform noise can cause rebuild thrash.

Navigation Invokers

1. Enable Generate Navigation Only Around Navigation Invokers in Navigation System settings.
2. Use Dynamic runtime generation.
3. Keep a NavMeshBoundsVolume covering the possible generation domain.
4. Add NavigationInvokerComponent or register an invoker.
5. Set generation radius from movement speed × worst tile-ready latency + path/look-ahead margin.
6. Set removal radius larger than generation radius to prevent boundary churn.
7. Test fast motion, teleport, multiple invokers, invokers far from seeds, and no-invoker cleanup.

Do not allow an agent to request a route beyond generated navigation without a waiting, partial-route, or fallback policy.

World Partition NavMesh

World Partitioned Navigation Mesh is Experimental in UE 5.8. It splits NavMesh into chunk Actors that stream with World Partition and supports Static, Dynamic Modifiers Only, and Dynamic modes.

Key rules:

• enable Is World Partitioned Navmesh on the RecastNavMesh;
• enable Fixed Tile Pool Size for streaming and size the pool for the maximum loaded navigation bubble plus editor visualization needs;
• disable automatic editor navigation updates for very large maps and require a deliberate final build;
• understand Base NavMesh Data Layers: base navigation includes navigation-relevant objects outside Data Layers, Editor Data Layers, and configured Base NavMesh Data Layers;
• Dynamic tile generation is limited to loaded space;
• build static WP navigation with WorldPartitionNavigationDataBuilder through the World Partition Builder Commandlet.

Acceptance

• clean commandlet build from source control;
• correct chunks load/unload with cells;
• no route crosses unloaded/missing collision;
• pool exhaustion and rapid traversal have explicit behavior;
• Runtime Data Layer state produces expected base/dynamic navigation;
• server paths and replicated movement remain correct;
• Experimental dependency and fallback are recorded for shipping review.